WorksheetsScience Class 10 chapter 1 chemical reactions and equations
Total questions: 15
Worksheet time: 8mins
A chemical reaction has taken place in which of the following process?
(i) Ice melts into water
(ii) A wet shirt got dried in sunlight
(iii) A brown layer is formed over iron rod kept in air
(iv) Sugar getting dissolved in water
A chemical reaction has taken place can be represented by which of the following condition?
(i) Evolution of gas
(ii) Heat released
(iii) Change in color
(iv) All the above
A chemical equation is said to be balanced if number of
(i) Compounds are same in both side
(ii) Molecules are same in both side
(iii) Number of atoms is same in both side
(iv) Number of electrons are same in both side
Write values of a,b and c if following chemical reaction is balanced .
aMg + bO2 → cMgO
(i) a=2, b=1, c=2
(ii) a=1, b=1, c=2
(iii) a=2, b=1, c=1
(iv) a=2, b=2, c=2
Which of the following reactions satisfies this condition? :
Iron nails kept with dilute sulphuric acid and ferric sulphite solution is formed and hydrogen gas is released.
(i) 2Fe(s) + 3H2 SO4(l)→ Fe2 (SO4)3(l) + 3H2(g)
(ii) 2Fe(s) + 2H2SO4(aq) → Fe2(SO4)3(s) + 4H2 (g)
(iii) 2Fe(s) + 2H2SO4 (aq) → 3Fe2(SO4)3(aq) + 2H2(g)
(iv) 2Fe(s)+3H2SO4 (aq) → Fe2(SO4)3 (aq) + 3H2 (g)
Calcium oxide reacts with water to form calcium Hydroxide. Which type of reaction is this?
(i) Combination and endothermic reaction
(ii) Combination and exothermic reaction
(iii) Decomposition and Endothermic reaction
(iv) Decomposition and exothermic reaction
On thermal decomposition of lead nitrate, nitrogen dioxide gas is evolved. How it presence can be verified?
(i) It will turn lime water milky
(ii) Rotten egg odour
(iii) Brown fumes can be observed
(iv) Reddish fume is observed
The chemical formula of lead sulphate is
(a) Pb2SO4
(b) Pb(SO4)2
(c) PbSO4
(d) Pb2(SO4)3
Chemically rust is
(a) hydrated ferrous oxide
(b) only ferric oxide
(c) hydrated ferric oxide
(d) none of these
The electrolytic decomposition of water gives H2 and O2 in the ratio of :
(a) 1 : 2 by volume
(b) 2 : 1 by volume
(c) 8 : 1 by mass
(d) 1 : 2 by mass
We store silver chloride in a dark coloured bottle because it is
(a) a white solid
(b) undergoes redox reaction
(c) to avoid action by sunlight
(d) none of the above
Rancidity can be prevented by
(a) adding antioxidants
(b) storing food away from light
(c) keeping food in refrigerator
(d) all of these
What is A and B ?
A - Hydrogen
B - Nitrogen
A - oxygen
B - Hydrogen
A - Hydrogen
B - oxygen
A - Nitrogen
B - Hydrogen
An element X on exposure to moist air turns reddish-brown and a new compound Y is formed. The substance X and Y are
(a) X = Fe, Y = Fe2O3
(b) X = Ag, Y = Ag2S
(c) X = Cu, Y = CuO
(d) X = Al, Y = Al2O3
What is the color of ash formed in this experiment ?
Black
Brown
White
Yellow
